Since the invention of non-volatile memory cells having both electrically erasable and electrically programmable capabilities as disclosed in U.S. Pat. No. 4,115,914 issued to Harari on Sept. 26, 1978; U.S. Pat. No. 4,203,158 issued to Frohman-Bentchkowsky et al on May 13, 1980, the commercial production of EEPROMs and Non-volatile RAMs that employ the thin tunnel dielectrics for electrically erasing and electrically programming has gradually become a reality. The Non-volatile RAM is the hybrid of a static random access memory cell and the non-volatile elements. It functions as the static random access memory under normal condition and it transfers the memory stored at the static random access memory cell to the non-volatile elements automatically when the power falls below certain limit. As the power recovers, it automatically transfers the memory from the non-volatile elements back to the static random access memory cell. One disadvantage of the Non-volatile RAM is its large cell size inherited from the static random access memory cell.